Cerathule
Well-known member
Do you have a link and a time reference for this please?
LED and BUD QUALITY
- Thread starter Tropical Sun
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greyfader
Well-known member
it's this one. at about 16 min he draws the curves. but when he's doing these hand drawings he's being approximate for purposes of illustration. i have watched this one before but i will do it again as i don't remember if he is making finite statements or approximate ones.
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Ca++
Well-known member
Regarding terp production, I just had an unexpected result. I switched the failing 400 I have ringed by QBs, with a decent 600, at the same height. Just 48 hours later, the smell in the room is one I associate with HID grows. On one hard, I could say I'm cooking some buds, releasing that smell. However, it's really quite strong, and a smell I have not associated with LED bud. Least, not in such an outstanding manner. It's been a few days now, and it's still coming. The speed in which this has occurred though, seems more like a conversion of products already there, than something new being produced.
It's just interesting at this point. Though could give reason to add HID just for a few days before harvest. If things pan out.
It's just interesting at this point. Though could give reason to add HID just for a few days before harvest. If things pan out.
greyfader
Well-known member
higher intensity means a higher metabolic rate.
LED/CMH.. She was grown on the LED side so mostly LED.
Ca++
Well-known member
Indeed, and I can't fail to miss, just how much the 6 is lighting things, compared to the 420w of LED around it. They should be equal, but seem very mismatched. The 400 seemed a better match, but I caught it cycle.
Bugbee can't really offer a finite answer. While all plants are different, he draws us to the fact all planting spacing also is. So while he takes care with drawing his graph, pausing where thought is needed, it can't get much more exact than it is. My own post is more encompassing. Giving both the top and bottom end of the range. As seen in different planting arrangements.
greyfader
Well-known member
one thing everyone should remember (when listening to Bugbee is that he and his students. like) most plant researchers use low levels of light while conducting experiments.
i think this negatively affects or skewers outcomes. i think things happen at higher intensities with cannabis that don't happen at lower ones.
since cannabis is a high-light plant, maybe it takes high intensity to turn on some processes to their fullest potential.
the other thing about Bugbee is that he owns Apogee Instruments and i think these little videos he puts out have some sales pitches woven into them.
editing this post to parenthesize the reference to Dr. Bugbee and his students using low-intensity light conducting experiments. i was wrong here so please disregard that statement.
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Ca++
Well-known member
Oh, there is no question he gets the Opogee name in, whenever he can. I think he is a director, as he shows commercial interest, but is unfamiliar with the product names.
I think he targets 950umol. I have seen it in a couple of talks, and calculated it from papers done with other professors. He has a preference for co2, and it seems 1200ppm is common. He also likes heavy peat mixes, above the other things he must trial.
He is paid to do research that matters. So his trials must have commercial viability. Like many, he recognises gains with higher intensity, but I think sees the risks it brings, growing huge buds that can rot unseen.
It's hard to get solid numbers, but I have pulled some from studies, that range from 650 to 900 grams per meter, in 8 weeks. Though the 900 was pie in the sky, as I tried to estimate walkway sizes, which is futile really.
He seems to be on target.
I think he targets 950umol. I have seen it in a couple of talks, and calculated it from papers done with other professors. He has a preference for co2, and it seems 1200ppm is common. He also likes heavy peat mixes, above the other things he must trial.
He is paid to do research that matters. So his trials must have commercial viability. Like many, he recognises gains with higher intensity, but I think sees the risks it brings, growing huge buds that can rot unseen.
It's hard to get solid numbers, but I have pulled some from studies, that range from 650 to 900 grams per meter, in 8 weeks. Though the 900 was pie in the sky, as I tried to estimate walkway sizes, which is futile really.
He seems to be on target.
With all due respect, this is totally false. The USU cannabis research team does lots of studies where they utilize an average ppfd of 1000+. Hell even in the course there were videos with fohse lights in the background. I honestly didnt see any experiments in chambers or greenhouse with low light in any of their modules. Where did you learn that they did studies/experiments in low lighting? Ive heard more the opposite, that Bugbees results are the result of high lighting, high co2 and more thus making his results harder to mimic.
greyfader
Well-known member
i think i read some of his papers where they used low levels but if they used higher levels i stand corrected.
The 1200ppm mark is when yield increases for the increase in co2 no longer matter. Above 1200 were at saturation, no more co2 will really add more yield or cannabinoid benefits. He has a graph with this curve illustrated as well. I hear love and hate for Bugbee but i freakin love the guy. Not only is he somehow just adorable but he has published more findings in agricultural development than most. He is detail oriented with his research and imo is the best resource for a scientific approach to cultivation. Since taking his courses and applying what Ive learned its changed my whole game for the better. Ive never had higher yield for the input of top shelf quality.
All good friend, just want to make sure were on the same page. I was mainly just curious which studies may have been at low light and wanted to point out that ive mainly seen high light experimentation w his team and him.
greyfader
Well-known member
i like and respect Dr Bugbee and have watched most of his videos and read a lot of his papers. it think that i have read so many papers that i may have gotten his work crossed up with someone else. but i have read many papers where the researchers used 400 umols ppfd and drew conclusions prematurely.
Cerathule
Well-known member
Thank you, I watched from 10 to 17 but he didn't state anything about how the measurement of the light compensation point was conducted. So it doesn't support what Ca++ stated. And his data, I mean, you realize it's handdrawn, so it's not precise by all means. This is a beginners video to illustrate some of the mechanisms of photosynthesis, not hard evidence. He states that Cannabis is a crop of high respiration, which, if we look how other plants' light compensation point is at 5 to 20 PPFD, still holds true at 60-100 PPFD. I'd rather believe Chandra here, because Bugbee almost put it at over 400. That's ridiculous to assume weed would die if lighten out by less, as he explains. The curve from Chandra still may be inaccurate, ie. extrapolated etc. The LCP can actually be measured at an individual leaf with great precision, it's sad this data is nowhere. Would even be interesting to see different chemotypes, and also, how it behaves with the age of the leaves.
Thegreengrower64
Well-known member
Two words. Joe pietri. 'High light plant'. Nah. Put your egos aside and do a little research.
Cerathule
Well-known member
Dude, you gotta stop your idiotic trolling ASAP. You have zero clue about what you are talking about. You realize it cannot even be done to measure the LCP of a total plant because irradiance diminishes with distance. The PPFD you got at the tops is not the same than say 10, 20 or 30cm in the depth of the canopy. Thus, you are having leaves with a different saturation. And this ratio would change drastically with plant height or age. So even if we measure O2 evolution of a whole plant at any given PPFD the result would be meaningless as it would only hold true for that specific plant structure. I told you already you are confusing the LCP with the DLI.
Cerathule
Well-known member
Prof. Chandra could record even an increase in photosynthesis rates above 2000PPFD so what makes you say "nah"...?
greyfader
Well-known member
well, good morning everybody! i want to apologize for my statement that Dr Bugbee uses low intensity while conducting research. i read and watched a bunch of his stuff last night.
he is actually one of the few that uses high-intensity lighting for research. my mistake!
nowhere does he state that cannabis is not a high light plant. pietri uses high intensity but for a shorter time period than 12 hours.
in my grows i used 1200 umols ppfd for 8 hours giving a DLI of 34.56 mols.
1000 umols for 12 hours is 43.2 mols per day for comparison.
in my current grow i've decided to push the plants hard and i am using 1200-1500 umols for 12 hours.
12 hours at 1200 umols is 51.84 mols and 1500 for 12 hours is 64.8 mols.
maybe you should do a little more reading before commenting.
he is actually one of the few that uses high-intensity lighting for research. my mistake!
and you have spoken without reading the content of this thread. i have been doing a series of grows for over two years using an 8-hour photoperiod. Joe Pietri is one of the sources of information i used.
nowhere does he state that cannabis is not a high light plant. pietri uses high intensity but for a shorter time period than 12 hours.
in my grows i used 1200 umols ppfd for 8 hours giving a DLI of 34.56 mols.
1000 umols for 12 hours is 43.2 mols per day for comparison.
in my current grow i've decided to push the plants hard and i am using 1200-1500 umols for 12 hours.
12 hours at 1200 umols is 51.84 mols and 1500 for 12 hours is 64.8 mols.
maybe you should do a little more reading before commenting.
